3.0 T MRI不同脉冲序列对胰腺疾病的诊断价值

目的 探讨MRI检查不同脉冲序列对胰腺病变的诊断价值。方法 对87例临床怀疑胰腺病变的病人应用3.0 T MR设备进行检查,扫描序列包括双回波T1WI（同相位与反相位成像）、脂肪抑制T1WI（T1WI+FS）、脂肪抑制T2WI (T2WI+FS)、磁共振胆胰管水成像（MRCP）、快速多层面扰相梯度回波(FSPGR)动态增强扫描。由2名放射科医师分析不同脉冲序列的MRI所见。结果 正常胰腺15例,急性胰腺炎27例,慢性胰腺炎30例,胰腺癌15例。T1WI+FS显示胰腺形态与信号最佳,正常胰腺呈稍高信号。在双回波T1WI上,胰腺与周围组织对比度降低。胰腺病变在T1WI上表现为低信号50例,T2WI+FS显示胰周渗出性病变34例。MRCP显示胰管扩张35例,胆管扩张20例,双管征9例。快速扰相梯度回波（FSPGR）动态增强显示胰腺癌13例,肿块在动脉期表现为相对低信号,延迟期轻度强化,周围血管受侵2例。结论 合理应用MR扫描序列有助于提高胰腺病变的诊断效能。     

胰腺疾病的MRI诊断

随着MBI成像技术的迅速发展和MBI的广泛应用，利用MBI诊断胰腺疾病正引起人们的普遍关注。现代MRI技术包括屏气T1加权成像及其脂肪抑制、T2加权成像及其脂肪抑制、MBI动态增强扫描、MR胰胆管成像和MR血管成像。这些脉冲序列各自有不同的组织对比机制，而且是互相补充的，它们的综合应用，可以较全面地评价胰腺及胰腺病变，从而明显改善了MBI对胰腺疾病的检测和诊断。本文着重介绍胰腺的MR成像技术，正常解剖、先天性异常和常见疾病的NR诊断价值。     

改良胰肾联合移植术后MR检查的价值

目的 探讨磁共振成像在胰肾联合移植术后的应用价值。方法 5例改良胰肾联合移植术后患者均用MR SE序列，磁共振胆管成像（MR cholangiopancreatography,MRCP)和磁共振尿路成像（MR urography,MRU)，动态钆喷替酸葡甲胺（Gd-DTPA)增强三维快速扰相梯度顺波磁共振血管成像（3D fast spoiled gradient recalled MRA,3D FSPGR MRA)和三维相位对比法磁共振血管成像（3D PC MRA）检查 分析各序列图像特点，并计算胰腺与腰大肌信号比（PPR）和胰腺实质强化平均在百分比（MPPE）。结果 5例中有2例移植体形态及信号完全正常，其中1例并发脾动脉末端动脉瘤。术后并发肾脏迟发性超急性排斥反应，胰腺急性排斥反应和胰腺慢性排斥反应各1例。肾脏迟发性超急性排斥反应MRI表现为皮髓质界线（CMD）消失，MRU未见肾集合系统及输尿管扩张，MRA见肾血管仅限于肾窦内。胰腺急性排斥反应MRI表现为胰腺增大，信号不均匀，MRA见胰腺血管吻合口通畅，PPR及MPPE分别为6．2和160％。胰腺慢性排斥反应MRI表现为胰腺体积缩小，实质信号尚均匀，MRCP示胰管扩张，MRA见胰腺血管稍细，PPR及MPPE分别为4．9和160％。结论 正确完善的MR扫描方法可客观反映移植体的形态及功能，是移植术后监测移植体的有效方法。     

胰腺外分泌功能的MRI研究进展

胰腺外分泌功能检查对胰腺生理功能研究及胰腺外分泌功能不全相关性疾病的诊断及疗效评估有十分重要的意义。近年来,多种MRI技术用于检测胰腺外分泌功能,如胰泌素刺激增强MR胆胰管水成像（s-MRCP）可进行功能诊断及分级,基于扩散加权的磁共振成像（DW-MRI）能够对主胰管内胰液的流速进行半定量检测,基于空间选择反转恢复脉冲的电影胆胰管水成像（CINE-MRCP）可直接观察胰管内胰液流动。综述常用胰腺外分泌功能MRI检查技术及应用进展。     

慢性胰腺炎:MR表现及相关病理学研究进展

慢性胰腺炎是指胰腺持续性、进行性炎症,导致不可逆的胰腺形态和功能改变.MRI已能全面评价胰腺的实质结构和功能.综述慢性胰腺炎的病理学、MR常规检查、MRCP及MR灌注成像的研究进展.     

胰腺浆液性微囊性囊腺瘤CT和MRI表现

目的 分析胰腺浆液性微囊性囊腺瘤(SMCA)的CT和MRI影像表现特征.方法 回顾性分析经手术病理证实的17例胰腺SMCA的CT及MRI表现,包括肿瘤位置、长径、分隔、增强表现及有无钙化、中央瘢痕、胰胆管扩张等影像表现.结果 17例SMCA:1例同时行CT和MR检查,10例行CT检查,6例MR扫描(其中2例同时行MRCP).病变位于胰头2例,胰颈2例,胰腺体尾部13例.肿瘤长径1.7~14 cm,平均5.2 cm.16例可见分隔,1例分隔显示欠佳,9例可见中央瘢痕.增强扫描分隔及瘢痕强化,囊性成分均无强化.6例可见远端主胰管扩张.结论 胰腺SMCA有一定的影像学特征,多表现为分叶状结节或肿物,具有多发小囊,囊腔多<2 cm,囊与囊之间见多发纤维分隔,增强扫描后纤维分隔明显强化,但低于胰腺组织.中央瘢痕是其特征性表现,在MR上多表现为T1WI及T2WI等或稍低信号.典型的胰腺SMCA根据CT和MRI表现可以做出明确诊断.     

移植肾的磁共振检查

近年来磁共振技术的迅速发展,使得评估移植肾功能成为可能.本文旨在介绍常规磁共振成像(MRI),磁共振血管成像(MRA),磁共振泌尿系统成像(MRU),MR灌注加权成像(PWI),MR弥散加权成像(DWI)和血氧水平依赖成像(BOLD)在移植肾检查中的应用和意义.     

胰腺实性假乳头状瘤影像学表现

目的 探讨胰腺实性假乳头状瘤的CT及磁共振成像(MRI)表现,提高该疾病的影像正确诊断率.方法 回顾性分析9例经本院手术病理证实的胰腺实性假乳头状瘤的影像表现,术前1例仅接受CT检查,6例仅接受MRI检查,2例同时接受CT及MRI检查.结果 本组9例病例均为单发病灶,大多数类圆形、椭圆形.胰头颈部2例,胰体尾部7例.直...     

胰腺损伤的MRI诊断

目的:总结胰腺损伤的MR征象,评价MRI在胰腺损伤诊断中的作用。材料和方法:回顾性分析5例急性闭合性腹部外伤伴胰腺损伤患者的MRI表现。其中男性3例,女性2例,年龄14-52岁,平均33.60±15.34岁。MRI检查用GE 1.5T超导全身磁共振机,相控阵列线圈,包括T_1WI、T_2WI及MRCP等序列。结果:胰腺损伤的MRI表现有:①胰腺肿大(2例);②胰腺断裂(4例);③主胰管断裂(4例);④胰腺内出血(1例);⑤胰周改变:5例均有胰周被膜和肾旁前筋膜增厚,胰周、肾旁间隙广泛积液;⑥假性囊肿形成(2例)。结论:胰腺损伤具有较特征的MR表现,结合临床,可以明确诊断。     

胎儿磁共振成像诊断新进展

目前,产前超声(US)仍是产科检查的首选影像方法,随着快速MR技术的发展,MRI已成为US的重要补充.本文在确定胎儿MRI检查安全性的基础上,综述快速MR技术的进展、正常胎儿的MRI表现以及MRI在胎儿疾病诊断中的应用.     

脑膜瘤的磁共振成像和质子磁共振波谱

探讨磁共振成像（ ＭＲＩ） 和质子磁共振波谱（１ Ｈ ＭＲＳ） 对脑膜瘤的诊断价值。材料和方法：３６４ 例行常规ＭＲＩ 检查, 其中１５ 例加做１ ＨＭＲＳ, 行肿瘤实质与健侧对应部位对照研究。结果： ＭＲＩ 平扫示： Ｔ１ ＷＩ５８ ．０ ％（２１１／３６４） 表现为等信号,３２ ．７ ％ （１１９／３４７） 为略低信号,９ ．３ ％ （３４／３６４） 为混合信号。Ｔ２ ＷＩ４０ ．１ ％ （１３９／３４７） 表现为等信号,４２ ．７ ％ （１４８／３４７） 表现为高信号,９ ．５ ％ （３３／３４７） 为略低信号,７ ．８ ％ （２７／３４７） 为混合信号。注射Ｇｄ － ＤＴＰＡ 后３３７ 例肿瘤实质部分均有不同程度的强化。６５ ．９ ％ （２２２／３３７） 出现“脑膜尾征”。５５ ．５ ％ （２０２／３６４）可见不同程度的水肿。１５ 例１ Ｈ ＭＲＳ 均表现为明显增高的胆碱（Ｃｈｏ） 峰,无氮乙酰门冬氨酸（ＮＡＡ） 峰,Ｃｈｏ／Ｃｒ（ 肌酸） 比值升高,ＮＡＡ／Ｃｒ 及ＮＡＡ／Ｃｈｏ 比值降低。４ 例出现乳酸峰（Ｌａｃ） 。结论：ＭＲＩ 平扫＋ 增强是诊断脑膜瘤的最主要方法,１ Ｈ ＭＲＳ 可作为很重要的补充。     

MR imaging and MR spectroscopy in prostate cancer management

Currently, endorectal coil MR imaging has the ability to improve accuracy in staging of localized prostate cancer. The addition of MR spectroscopic imaging has further improved the sensitivity of MR imaging for intraprostatic tumor localization. Additional refinements and techniques are expected to further improve the performance of MR imaging for prostate cancer imaging and to aid in patient management. Further studies are required to identify the ideal role for MR imaging in the diagnosis and management of prostate cancer.     

MR imaging and MR spectroscopy in rhizomelic chondrodysplasia punctata

A case of rhizomelic chondrodysplasia punctata was investigated with MR imaging of the brain and hydrogen-1 MR spectroscopy of the brain and blood. Areas with abnormal signal hyperintensity on T2-weighted images or hypointensity on T1-weighted images were detected in the subcortical white matter. MR spectroscopy of the brain showed that normal-appearing white matter was characterized by increased levels of mobile lipids and myo-inositol, reduced levels of choline, and the presence of acetate. The importance of these metabolic anomalies is correlated to the deficiency in plasmalogen biosynthesis.     

MR imaging and MR arthrography of paraglenoid labral cysts

OBJECTIVE: We investigated the pathophysiology of paraglenoid labral cysts on the basis of MR imaging, MR arthrography, and cyst aspiration. MATERIALS AND METHODS: From 2211 MR imaging examinations, 51 (2.3%) cysts in 46 patients were identified. MR arthrography (n = 5), cystography (n = 1), arthroscopy (n = 17), percutaneous needle aspiration (n = 4), and medical records were also reviewed (n = 46). RESULTS: On MR imaging and arthrography, cysts were best viewed on T2-weighted images. Mean cyst diameter and volume were 2.2 cm and 2.8 cm3, respectively. Fifty-seven percent of cysts were located adjacent to the posterior labrum. On MR imaging and arthroscopy, a labral tear was identified in 27 (53%) and 15 (88%) patients, respectively. Eight cysts that caused compression neuropathy were large (mean size, 3.1 cm; p = 0.04) and located next to the posterior or inferior labrum. In four of five patients, MR arthrograms showed no intraarticular contrast material in the cyst. Cystograms showed no communication with the glenohumeral joint space, and cyst aspiration resulted in temporary symptom relief; however, cysts recurred in three of four patients. CONCLUSION: Most paralabral cysts are associated with labral tears. Paralabral cysts may be difficult to identify on MR arthrography unless a T2-weighted sequence is performed. Direct communication between a cyst and joint space rarely occurs. A posterior or inferior cyst may cause compression neuropathy of the suprascapular or axillary nerve, respectively. Cyst aspiration may result in temporary relief of symptoms, but an untreated labral tear should be suspected if cysts recur.     

Subtraction MR Venography Acquired from Time-Resolved Contrast-Enhanced MR Angiography: Comparison with Phase-Contrast MR Venography and Single-Phase Contrast-Enhanced MR Venography

ObjectiveTo evaluate the image characteristics of subtraction magnetic resonance venography (SMRV) from time-resolved contrast-enhanced MR angiography (TRMRA) compared with phase-contrast MR venography (PCMRV) and single-phase contrast-enhanced MR venography (CEMRV).ResultsSingle-phase contrast-enhanced MR venography showed better image quality (median score 4 in both reviewers) than did the other two MRVs (p < 0.001), whereas SMRV (median score 3 in both reviewers) and PCMRV (median score 3 in both reviewers) had similar image quality (p ≥ 0.951). SMRV (median score 0 in both reviewers) suppressed arterial signal better than did the other MRVs (median score 1 in CEMRV, median score 2 in PCMRV, both reviewers) (p < 0.001). The dural sinus score of SMRV (median and interquartile range [IQR] 48, 43-50 for reviewer 1, 47, 43-49 for reviewer 2) was significantly higher than for PCMRV (median and IQR 31, 25-34 for reviewer 1, 30, 23-32 for reviewer 2) (p < 0.01) and did not differ from that of CEMRV (median and IQR 50, 47-52 for reviewer 1, 49, 45-51 for reviewer 2) (p = 0.146 in reviewer 1 and 0.123 in reviewer 2). The SNR and CNR of SMRV (median and IQR 104.5, 83.1-121.2 and 104.1, 74.9-120.5, respectively) were between those of CEMRV (median and IQR 150.3, 111-182.6 and 148.4, 108-178.2) and PCMRV (median and IQR 59.4, 49.2-74.9 and 53.6, 43.8-69.2).ConclusionSubtraction magnetic resonance venography is a promising MRV method, with acceptable image quality and good arterial suppression.     

MR imaging,MR angiography,and MR spectroscopy of the brain in eclampsia.

PURPOSETo compare the MR imaging and MR angiographic changes with in vivo proton MR spectroscopic findings and to determine the spectral differences between edema and ischemia in patients with eclampsia.METHODSSpin-echo MR imaging, MR angiography, and single-voxel proton MR spectroscopy were performed in 10 patients with eclampsia. MR studies were obtained within 3 to 5 days of diagnosis and repeated after 2 weeks with identical parameters.RESULTSMultifocal subcortical/cortical hyperintensities were noted in all 10 patients on T2-weighted images; in two patients, hyperintensities were seen in both cerebral hemispheres. In nine patients, MR angiograms showed narrowing of the major vessels constituting the circle of Willis that resolved after 2 weeks. In one patient with subtle imaging changes, MR angiography showed mild bilateral narrowing of the proximal middle and posterior cerebral arteries that did not change after 2 weeks, whereas imaging abnormalities worsened. Findings at single-voxel MR spectroscopy of the reversible T2 hyperintense lesions were significantly different from findings in the control group for N-acetylaspartate (NAA)/creatine ratios. One patient with mild abnormalities at MR imaging and MR angiography had lactate and decreased creatine and NAA, and on a follow-up study had a further decrease of NAA and creatine as well as a decrease in lactate.CONCLUSIONIn vivo proton MR spectroscopy may help to differentiate cerebral edema from ischemia in patients with eclampsia and thus may help to determine the prognosis for these patients.